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Flashcards in Immuno 4 Deck (38)
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1
Q

all antibodies are of a class of protein called

A

immunoglobulin

2
Q

structure of an immunoglobulin

A

4 polypeptide chains bound together by disulfide bonds

2 light chains, 2 heavy chains

3
Q

what are the 2 regions of the immunoglobulin

A

variable and constant region

4
Q

variable region of an immunoglobulin

A

(also called FAB- fragment antigen binding)
-the end of the immunoglobulin and the one that forms the structure that will bind to a specific antigen (fingers), variations

5
Q

constant region of an immunoglobulin

A
  • backbone that doesn’t have as many variable combinations (only varies from one class to another)
  • (also called fragment Fc region)
6
Q

5 immunoglobulins and percentages

A
  1. IgG - 80%
  2. IgA - 15%
  3. IgM - 5%
  4. IgD - 0.2%
  5. IgE - 0.002%
7
Q

where is IgG usually found

A

epithelial tissue such as skin and conjunctiva of the eye

8
Q

IgG is primarily responsible for

A

fixation of complement and opsonization

9
Q

IgG is the principle source of ____ immunity against organisms in _____ space

A

humoral immunity against organisms in extravascular space

10
Q

IgA is associated with ___ tissue

A

epithelial

11
Q

what is IgA in the blood stream versus in the tissue

A

blood: monomer
tissue: dimeric

12
Q

what is secretory IgA

A

is after dimer and secretory component are added

-it bathes epithelial tissue

13
Q

how does secretory IgA work?

A

it inhibits virus particles from sticking on from epithelial surface- “it slides off like teflon paint”

14
Q

in secretory IgA, what forms the monomers and what connects them to make a dimer

A

monomers are produced by lymphocytes

-dimer formed from connections from J chain

15
Q

a unique feature of IgM is its

A

high molecular weight

5 monomers

16
Q

IgM is especially efficient at

A

fixing complement (at attaching complement once it is activated to the invading organism)

17
Q

what immunoglobulin is “first at the scene” at the site of infection

A

IgM

18
Q

role of IgM is protecting _____ space

A
intravascular space 
(blood vascular system inside the vessels)
19
Q

IgD

A

nearly all IgD appears on the surface of lymphocytes (like IgM does too)- so could be related or coordinated with IgM

20
Q

IgE is also called the

A

“skin sensitizing antibody”

21
Q

IgE normally has a physiological role to

A

protect mucosal surfaces

22
Q

IgE triggers release of certain agents that start inflammation response such as

A
  • vasodilation of blood vessels

- chemotactic factors which attract macrophages

23
Q

what is an allergy (hypersensitivity)?

A

an exaggerated immune response

24
Q

type I hypersensitivity is also known as

A

immediate Rx, anaphylaxis

25
Q

what occurs during initial exposure during type I hypersensitivity ?

A

B cells -> plasma cells, plasma cells produce type of IgE called reagin which binds to mast cells

26
Q

what occurs during second exposure during type I hypersensitivity ?

A

allergen binds to IgE, destabilizing the cell membrane which bursts (if the allergen bridges two IgE molecules)
-explosive degranulization releases components from mediators

27
Q

explosive degranulation causes the mediators to release :

A
  • histamine
  • heparin
  • prostaglandins
  • proteolytic enzymes
28
Q

the mix of mediators in type I hypersensitivity causes

A
  • smooth muscle contraction
  • vasodilation (redness)
  • increased vascular permeability (tissue starts to lose fluid)
  • mucous secretion (causing hay fever symptoms)
29
Q

what occurs with the mast cell in immediate hypersensitivity?

A

all those packets of mediators inside the mast cells blow up and released all at once

30
Q

what occurs in systemic anaphylaxis

A

release of a bunch of mast cells throughout the body:
-smooth muscle contraction and bronchioles constrict
-arterioles dilate, drastically reducing blood pressure
-permeability of the vessels increases and they start losing fluid
(shock)

31
Q

what occurs during localized anaphylaxis

A

localized release of mediators- often in mucous membrane, resulting in hay fever
-if in lower respiratory tract, bronchial asthma (deeper and airborne)

32
Q

type IV hypersensitivity is also called

A

cell-mediated, delayed

33
Q

what occurs during onset on type IV hypersensitivity

A

subset of T lymphocytes called delayed type hypersensitivity cells (TH1) recognize antigen, react, and release cytokines which can cause tissue damage

34
Q

process during type IV hypersensitivity

A
  • T lymphocytes recruited via cytokines
  • cytokines increase capillary permeability: macrophages have exaggerated response (tissue damage)
  • special T cells amplify the whole thing
35
Q

why is it called delayed hypersensitivity

A

the whole process for T cells to proliferate, send out cytokines, and recruit macrophages can take a day or two

36
Q

type IV hypersensitivity is involved in what pathologies

A
  • autoimmune diseases
  • transplant rejection
  • killing cancer cells
  • contact dermatitis
37
Q

what is contact dermatitis

A

occurs with certain products (cosmetics, TPAs, metals)

-it is an immune reaction to something that isn’t biologic

38
Q

how can contact dermatitis illicit an immune response

A

small molecules called haptens when attached to a carrier (protein in the skin)- this combination is antigenic